Miniature optical projectors are used in a variety of applications. For example, such projectors may be used to cast a pattern of coded or structured light onto an object for purposes of three-dimensional (3D) mapping of the projected objects (also known as depth mapping).
Optical projectors may, in some applications, project light using one or more diffractive optical elements (DOEs). For example, U.S. Patent Application Publication 2009/0185274, whose disclosure is incorporated herein by reference, describes apparatus for projecting a pattern that includes a first DOE configured to diffract an input beam so as to generate a first diffraction pattern on a first region of a surface, the first diffraction pattern including a zero order beam. A second DOE is configured to diffract the zero order beam so as to generate a second diffraction pattern on a second region of the surface such that the first and the second regions together at least partially cover the surface.